Motor theory is confusing. LOL. I do know that the Stepper driver is using PWM to control the voltage. The pulses in the PWM output are peaking at 48V they are very short pulses though and so the average voltage is MUCH smaller. Why 48V is better than 24V is something I am still figuring out.
Sorry… I am wrong. BLDC motors have low winding resistances. Stepper Motors have relatively higher resistances. 5 ohms seems common. Still 48V through 5Ohms is still 9.6A. So the PWM thing is still correct.
Oh ok! 
I was thinking with the motors completely standstill that 2 amps were continuously flowing through the coils. Anyways, will report back tomorrow on the X axis. Thank you all!
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Its all about the torque of the motor when you are comparing 48V over 24V.
Sort of like hammering a nail with a 10 pound hammer versus a 1 pound hammer. The nail is going to go the same distance, but it will move more quickly with the 10 pounder.
I went ahead and bumped up motor currents to 2.03 amps RMS. They are still cool enough to touch easily.
Still trying to track down whether this is a software issue, I’ve messed with the belts for probably 3 hours total now so I hope that can’t be it. Side note: we really could use a better belt tensioner design. They slip way too easily when trying to hold an allen key and pushing downard at the same time while holding tongue at right angle.
There was a thread recently about making custom fancy ones:
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It’d be great if these could be purchased and for the Shapeoko Pro. Running our business we don’t have time to make tensioners unfortunately!
I’m starting to wonder if a flat tipped set screw for the flat portion of the D shaft of the motor would be a better option for securing the pulleys than the standard supplied cup point set screw.
So, that’s what we did today. And it turns out the pulley grub screws are M4 and not M3 now.
Used M4x8mm screws, which are actually about 2mm longer than need-be, however, should the head ever break off you have something to grab on to with a vise grip.
Turns out the X axis is basically impossible to get tight enough, there’s a consistent 0.2mm of backlash which is most likely attributed to the belt clip slipping before the belt is pinched at the end, even with using longer bolts to try and use as an aid. We even exposed a fresh portion of belt that goes through the clip to try and see if that would help; nope.
The only thing I can think of to prevent this would be to super glue the belt together at the end and then tighten it.
Any other simple ideas would be greatly appreciated. We cannot open sales again until this is resolved.
Can you get a close-up of the belt tensioner?
Hi Neil, here is the tensioning side of our X axis; as noted, the longer bolt didn’t even really help us at all other than being easier to start the tensioning process.
So is the belt loose? I don’t think you’d get that much backlash from the clip.
If it’s loose, then it isn’t from a lack of effort is what I’m trying to say. I think it comes down to the (bad) design of the clip.
Any suggestions on improving it or should we just super glue the belt end and then take advantage of the longer length bolt (without bending motor shaft of course).
Why is your use of that belt tension different than other’s use? Is it that the laser exposes the result of the backlash where the router/spindle masks the problem?
Or, is there still something else causing the problem?
That’s what I’d like to know too. We’re literally at a point where if there’s anyone close in TX willing to help, that would be awesome. 
Someone could make a killing selling belt tensioners.
Do you have a 3D printer?
Yes but it’s been down for awhile. I could pay someone to machine the parts if necessary though Neil.
I could widen these and send them to you, but I’m not convinced that your issue is belt tension.
Cool design! Do you have a photo of them installed? Whatever you’re willing to help with, all is great
I measured about 0.2mm of lost motion on X earlier, and that was after tightening the X stepper mount block, idler bearing bolts, and then belts again.
Would it be caused by no forces on it when using a laser. When using it with a spindle its got some pressure against the piece its cutting in to which maybe keeps a load on the belts.